A plasma generator could provide a kind of efficient and clean heat source, i.e. plasma flow, for use in the field of industry, such as ignition of a burner in a power station, cutting, jointing, spraying, metallurgy, chemical industry, and waste treatment, and the field of science, such as material and aerospace. The heated plasma has very high temperature and high enthalpy, and comprises a great number of electric particles (electrons and ions), which is different from the high-temperature gas created by chemistry burning. A plurality of processes that could not be realized in the past can be realized well under the condition of plasma.
After 2000 years, direct current (DC) plasma ignition technology has been successfully used in coal-powder burners. The so called DC plasma ignition technology means that the DC current starts arc under certain medium pressure, and obtains directionally flowing air plasma with steady power through the control of a strong magnetic field. The plasma will create a local high temperature fire core with great temperature gradient in the ignition burner, wherein the temperature is higher than 4000K. The coal powder particles release volatile material and re-creates volatile material, being broken and pulverized, and then burn quickly when pass through the plasma “fire core”, so as to achieve the objection of ignition and accelerating the burning of coal-powder. The technology has been well-known for the ignition without oil.
However, the DC ignition technology is limited by its technical weakness and has a plurality of problems. At present, hot cathode DC plasma ignition technology with high current and hot electrons ejection is mainly used. In the utilization of this technology, the current increases along with the power increasing. So the power of DC plasma ignition will be hardly more than 150 kW. And the life of cathode is less than 50 Hours. The cathode has to be made from precious metal and its price and running cost are both very high. The cost of rectifier power system for DC plasma ignition technology is high and its volume is huge.
Therefore, the present invention is intended to overcome the above limitations.